Ukraine's leader on Thursday accused Moscow of building a new Cold War wall across Europe "between freedom and bondage," as his government said Russian shelling had killed 21 more civilians.
Three weeks into their devastating invasion, Russian forces also stood accused of bombing a theatre sheltering many civilians and marked with the word "children."
Kyiv emerged from a 35-hour curfew to its own fresh destruction, as Russian troops strive to encircle the Ukrainian capital as part of their slow-moving offensive.
Beneath a Kyiv apartment block damaged by a downed rocket, AFP journalists saw a distraught man crouched over a body draped in a bloodstained cloth.
The 21 were killed when overnight artillery fire pounded a school and a cultural centre in the town of Merefa outside the hard-hit eastern city of Kharkiv, regional prosecutors said.
In besieged Mariupol to the south, from which officials say 30,000 civilians have now fled, rescuers were combing through the smoking rubble of the Drama Theatre.
Ukrainian officials said more than 1,000 civilians had been sheltering in a basement bomb shelter beneath the theatre, and that Russian shelling was continuing. Human Rights Watch said it was at least 500.
'Tear down this wall'
President Volodymyr Zelensky said the "number of dead is not yet known" at the theatre, but the airborne attack showed "Russia has become a terrorist state."
Zelensky addressed the German parliament a day after a speech to the US Congress, when he secured $1 billion in new US military aid, including Stinger anti-aircraft missiles used against Soviet forces in Afghanistan.
Zelensky reached back to that Cold War era as he drew on a 1987 speech in Berlin by US president Ronald Reagan: "Dear Mr Scholz, tear down this wall," he implored German Chancellor Olaf Scholz.
"It's not a Berlin Wall -- it is a wall in central Europe between freedom and bondage and this wall is growing bigger with every bomb."
'It is hell'
US President Joe Biden called Putin a "war criminal," triggering fury in the Kremlin, as the Russian leader also lashed out at "scum and traitors" at home who he said were undermining the war effort.
Without offering evidence, Russia's defence ministry accused Ukraine's far-right Azov Battalion of blowing up the theatre in Mariupol.
Local officials say more than 2,000 people have died so far in indiscriminate Chechnya-style shelling of the port city.
People fleeing Mariupol said they were forced to melt snow for drinking water and cook food scraps on open fires, with water and power supplies cut off.
Escaping default
Addressing the Bundestag by video, Zelensky issued a strong rebuke of Germany's years-long reluctance to sever energy and business ties with Russia.
However, Nato members have resisted Zelensky's pleas for direct involvement through a no-fly zone over Ukraine, warning it could lead to World War III against nuclear-armed Russia.
Putin, at a televised government meeting on Wednesday, insisted the invasion was "developing successfully", adding: "We will not allow Ukraine to serve as a springboard for aggressive actions against Russia."
However, Russia's finance ministry said Thursday it had made interest payments worth $117.2 million on two foreign bonds, avoiding a default for now.
From rackets to rifles
More than three million Ukrainians have fled across the border, mostly women and children, according to the UN.
With stop-start peace talks ongoing, officials in Kyiv said Russia had agreed to nine humanitarian corridors Thursday for fleeing refugees, including one out of Mariupol.
Kremlin spokesman Dmitry Peskov had said a "compromise" outcome in the talks would centre on Ukraine becoming a neutral state comparable to Sweden and Austria -- an idea roundly rejected by Kyiv.
Pro-Kremlin Chechen strongman Ramzan Kadyrov said 1,000 fighters led by one of his relatives were en route to Ukraine "to take part in the special operation of denazification and demilitarization of Ukraine."
Ukraine has asked Turkey to be a guarantor of any future deal with Russia, along with the UN Security Council's five permanent members and Germany, Turkish Foreign Minister Mevlut Cavusoglu said.